source: binary-improvements/MapRendering/Web/Handlers/ItemIconHandler.cs@ 246

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Threading;

using UnityEngine;

namespace AllocsFixes.NetConnections.Servers.Web.Handlers
{
        public class ItemIconHandler : PathHandler
        {
                private string staticPart;
                private bool logMissingFiles;
                private Dictionary<string, byte[]> icons = new Dictionary<string, byte[]> ();
                private bool loaded = false;

                public ItemIconHandler (string staticPart, bool logMissingFiles, string moduleName = null) : base(moduleName) {
                        this.staticPart = staticPart;
                        this.logMissingFiles = logMissingFiles;
                }

                public override void HandleRequest (HttpListenerRequest req, HttpListenerResponse resp, WebConnection user, int permissionLevel) {
                        if (!loaded) {
                                if (!LoadIcons ()) {
                                        resp.StatusCode = (int)HttpStatusCode.NotFound;
                                        Log.Out ("Web:IconHandler: Could not load icons");
                                        return;
                                }
                        }

                        string fn = req.Url.AbsolutePath.Remove (0, staticPart.Length);
                        fn = fn.Remove (fn.LastIndexOf ('.'));

                        if (icons.ContainsKey (fn)) {
                                resp.ContentType = MimeType.GetMimeType (".png");
                                resp.ContentLength64 = icons [fn].Length;
                                resp.OutputStream.Write (icons [fn], 0, icons [fn].Length);
                        } else {
                                resp.StatusCode = (int)HttpStatusCode.NotFound;
                                if (logMissingFiles)
                                        Log.Out ("Web:IconHandler:FileNotFound: \"" + req.Url.AbsolutePath + "\" ");
                                return;
                        }
                }

                private bool LoadIcons () {
                        lock (icons) {
                                if (loaded) {
                                        return true;
                                }

                                GameObject atlasObj = GameObject.Find ("/NGUI Root (2D)/ItemIconAtlas");
                                if (atlasObj == null) {
                                        Log.Error ("Web:IconHandler: Atlas object not found");
                                        loaded = true;
                                        return false;
                                }
                                DynamicUIAtlas atlas = atlasObj.GetComponent<DynamicUIAtlas> ();
                                if (atlas == null) {
                                        Log.Error ("Web:IconHandler: Atlas component not found");
                                        loaded = true;
                                        return false;
                                }

                                Texture2D atlasTex = atlas.texture as Texture2D;

                                foreach (UISpriteData data in atlas.spriteList) {
                                        string name = data.name;
                                        Texture2D tex = new Texture2D (data.width, data.height, TextureFormat.ARGB32, false);
                                        tex.SetPixels (atlasTex.GetPixels (data.x, atlasTex.height - data.height - data.y, data.width, data.height));
                                        byte[] pixData = tex.EncodeToPNG ();

                                        icons.Add (name, pixData);
                                        UnityEngine.Object.Destroy (tex);
                                }

                                loaded = true;
                                Log.Out ("Web:IconHandler: Icons loaded");

                                return true;
                        }
                }
        }
}